Process for the production of a topographical map having a relief contour effect

ABSTRACT

A photo-mechanical process for the production of a topographical map having a relief contour effect wherein a positive print is obtained through a shifted overlay including a positive transparency form of the map, a positive mask transparency of selected contour lines of the map, and a negative transparency form of the map; thereafter obtaining a negative print with the use of the negative form, the mask and the positive form individually; and finally preparing a final print through the negative and positive prints.

United States Patent [1 1 Fraser Aug. 21, 1973 PROCESS FOR THE PRODUCTION OF A TOPOGRAPHICAL MAP HAVING A RELIEF CONTOUR EFFECT [52] US. Cl. 96/41, 96/44 [51] Int. Cl G03c 5/04 [58] Field of Search 96/41, 44, 27, 42, 96/43 [56] References Cited UNITED STATES PATENTS 3,622,323 11/1971 Fraser 96/41 3,116,675 1/1964 Trimble 2,309,752 2/1943 Cooke 96/41 3,338,766 8/1967 Agnew 945/41 Primary Examiner-Norman G. Torchin Assistant Examiner-Edward C. Kimlin Attorney-Watson, Cole, Grindle & Watson [5 7 ABSTRACT A photo-mechanical process for the production of a topographical map having a relief contour effect wherein a positive print is obtained through a shifted overlay including a positive transparency form of themap, a positive mask transparency of selected contour lines of the map, and a negative transparency form of the map; thereafter obtaining a negative print with the use of the negative form, the mask and the positive form individually; and finally preparing a final print through the negative and positive prints.

3 Claims, 10 Drawing Figures I PROCESS FOR THE PRODUCTION OF A TOPOGRAPHICAL MAP HAVING A RELIEF CONTOUR EFFECT transparency form by shading a selected portion of the contour lines seen to depict that side of the hill or valley which is shaded if a ray of light were beaming across the topography print. The positive transparency is then laid over the positive mask and negative transparency so that the contour lines of the two transparencies are coincident, and the positive transparency is slightly shifted downwardly and to the right along a 45 line approximately equal to the thickness of the contour lines which lie perpendicular to such 45 line. A positive print, as shown in FIG; 7 of this patent, is thereafter obtained after exposing through this shifted overlay.

Another three-ply overlay is an arrangement of the type similar to that described above except that a negative mask is used in place of the positive mask between the positive and negative transparencies, the negative mask having been prepared from the positive mask. The shift of the positive transparency in this overlay is made upwardly and to the left along a 45 line equal to approximately the thickness of a contour line which lies perpendicular to such 45 line. A negative print, as shown in FIG. lllof the above-mentioned patent, is obtained in any normal manner after exposing through this second overlay. The positive and negative prints are then sequentially placed on a white base film and exposed to obtain both the lightened and darkened portions of the contour lines. The base film is then developed into the finished product as shown in FIG. 11 of the patent.

It has now been discovered that, by using the same shifted overlay of the positive transparency-positive mask-negative transparency and exposing through each of them separately, a negative print of the type shown in FIG. of the patent may be obtained. Accordingly, it is not necessary to prepare a negative mask or a second shifted overlay using such a mask of the type shown in FIGS. 8 and 9 of the patent. The same final print of the topographical map having the same unique relief contour effect is therefore obtainable in less time because fewer steps are required. Also, fewer materials are required, so that a more efficient and economical operation is now made possible.

It is therefore a principal object of the present invention to produce a relief effect for topographical maps by means of a photo-mechanical process in a more expeditious, economical and time-saving manner as compared to that of the prior art.

Another object of this invention is to provide such a process where both a positive and negative print may be obtained of the contour lines ultimately to be depicted for the lightened and darkened sides of the hills and valleys represented by a topographical map, both shifted overlay.

rately exposing through each of these three plies of the. I

same shifted overlay.

A still further object of the present invention is to provide such a process wherein the shift takes place along a 45 line with respect to the overlay so that the widths of the various contour lines are at a maximum for those lines lying perpendicular to such 45 line across the map, and wherein the various contour lines are at a minimum across their width for those portions of contour lines lying parallel to such 45 line, the widths of those portions of the lines between minimum and maximum gradually varying in width.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a plan'view showing a positive transparency made of the map contour lines;

FIG. 2 is a plan view 'of a negative transparency form taken from the form of FIG. 1;

FIG. 3 is a plan view showing a positive mask after being prepared from the FIG. 1 transparency;

FIG. 4 is a sectional view showing an overlay of the positive transparency, the positive mask and the negative transparency;

FIG. 5 is a plan view of the positive printobtained by an exposure through the FIG. 4 overlay;

FIGS. 6c, 6b and 6a are, respectively, sectional views of the positive transparency, the positive mask, and the negative transparency as they are used in producing the negativev print by separately exposing through they shifted overlay; 1

FIG. 7 is a plan view of the print obtained in negative form from the separate exposure through the shifted overlay plies; and

FIG. 8 is the final print produced from the FIG. 5 and FIG. 7 prints.

Turning now to the drawings wherein like reference characters refer to like and corresponding parts throughout the several views, it can be seen that each of the FIGS I through 5 is substantially the same as FIGS. 1, 2, 3, 6 and 7, respectively, of my prior patent, No. 3,622,323. Therefore, the same'reference numerals as on the corresponding figures will be used in the interest of clarity. Tuming to FIG. I, a positive transparency form 20 is shown as having a plurality of contour lines thereon. As before, this type of form may be one which is used in the conventional topographic map processes, so that it is readily available and need not be specially produced. Accordingly, the present technique is supplementary to the total mapping process commonly practiced, so that the normal procedure may be interrupted just long enough to make a contact print in carrying out the invention. A negative transparency form 21 is then produced from form 20 or, in the alternative, form 21 may be a form used in the conventional topographic map process from which the positive transparency form 20 is subsequently produced.

A positve mask 22 is then produced on a transparency either in accordance with the technique described in the aforementioned patent or by the uninterrupted masking of a select portion 34 of each of the contour lines. The two techniques are carried out in substantially the same manner except that the uninterrupted masking procedure may be slightly more convenient for the operator. Turning to FIG. 3, the portions selected for masking are those lines which depict the side of the hill or valley which would be shaded if a ray of light were beaming across the topography. The masking for the predicted darkened lines is carried out by placing a blank transparency over the positive transparency form and thereafter rotating both transparencies counterclockwise throughout 45 so that the 45 line 23 is horizontal with respect to the operator. A dark ink marking pen or the like is then used for shading a portion 34 of each darkened contour line so as to produce masking areas 24. Portions 34 of the contour lines are selected for shading in such manner since they are seen to depict the dark side of the mountain or valley represented by the map, assuming that a light is shining in the direction of line 23 from its upper to its lower end. Shading areas 24 are, therefore, drawn to completely mask out these contour line portions. As before, the person preparing this mask can assure himself of the correct amount of shading by remembering that the contour line portions 34 must be shaded not beyond those changes in line direction shown, for example, as at 25.

The final print of the topographical map having a relief effect of the type in accordance with the present invention, is obtained by producing two separate transparency prints, the first being a positive of the so-called remaining portions 33 of each of the contour lines, and the second being a negative of each of the so-called select portions 34 of each of the contour lines. These select portions 34 are those contour line portions lying directly beneath the masking areas 24 as shown in FIG. 3.

After the three transparencies 20, 21 and 22 are obtained as outlined above, the positive mask 22 is arranged to overlie the negative transparency form 21 in a manner whereby the shading areas 24 will completely mask the select portions 34 of each of the negative contour lines on form 21. The select and remaining contour portions 34, 34' and 33, 33', respectively, are

shown in FIGS. 1 and 2 for only several of the contour,

lines thereon, in the interest of clarity.

The positive transparency form 20 is placed over the masked negative transparency form 21 in such a manner that the positive contour lines of form 20 are coincident with respect to the negative contour lines of form 21, which can be clearly gathered from FIG. 4 if form 20 had not been moved rightward a distance equal to SHIFT. The negative lines on form 21 would therefore each be masked by the positive lines of form 20. However, form 20 is shifted along a 45 line similar to 23, a distance equal to SHIFT equal to approximately the width of a contour line lying perpendicular to the 45 line 23. After the overlay is so shifted, the remaining portions 33 on the negative transparency form 21 will be open to allow light to pass therethrough from above form 20, as depicted by the light ray paths 26. The select portions 34' of the contour lines on form 21 continue to be masked by the masking area 24, so that shifting of the line portions 34 with respect to 34' does not serve to likewise open the selected portions 34'. Shifting of the form 20, however, does not fully open the negative line portions 33'. Only those portions of line 33 which lie perpendicular to the line 23 will be so fully opened, while those portions of lines 33 lying other than perpendicular with respect to the 45 line 23 are only partially opened. Accordingly, that portion of each line 33, lying between a perpendicular position with respect to line 23 and a parallel position with respect thereto, will remain partially hidden by line 33 on form 20 to a greater or lesser extent.

The shifted overlay shown in FIG. 4 is exposed onto a positive print 36 so that the first of two prints (FIG. 5) is prepared for obtaining a final relief effect (to be hereinafter described). Printing of the FIG. 5 form 36 can be carried out in any conventional manner so long as a positive'is produced on a transparency. Also, it should be noted that the stippled areas of FIG. 4 represent blockage of light rays from above each of the three plies with respect to the next underlying ply.

In contrast to my above-mentioned prior patented technique, the shifted overlay of forms 20,22,21, shown in FIG. 4, is now used to produce not only the positive print 36 but also the negative print 37 for the remaining contour line portions 34'a. Turning to FIG. 6a, it can be seen that form 37 is first exposed through negative contour line portion 33', 34, thereby leaving a series of exposed line portions 41 on the form 37. The remaining areas 43 on the form 37 remain unexposed.

Additional portions of form 37 are exposed through the positive mask 22 (see FIG. 6b) in such a manner whereby only that portion directly beneath the masking area 24 remains unexposed during this second independent operation. All but such portion of form 37 is therefore exposed as at 42, while those portions directly underlying the shaded area 24 remain unexposed as at 43.

The third independent exposure step of this operation, as shown by FIG. 60, consists of exposing a required area of portions 43 while masking the remaining portion thereof by means of select contour line portions 34 of the positive transparency 20. Of course, the remaining contour line portions 33 of this positive transparency form have no further effect on exposure or masking with respect to the form 37. Since the form 20 is in a position shifted to the right with respect to forms 22 and 21, those portions 34'a, which remain unexposed to form the negative print 37 of FIG. 7, are obtained by reason of this shift between 21 and 20 since the 34'a negative line portions remain unexposed for the same reason that they are masked in the FIG. 4 embodiment. For example, contour line portions 34 and masking area 24 preserve those negative line portions 34'a upon shifting, while in FIG. 4 the contour line portions 33 open the line portion 33 for exposure in somewhat a reverse manner. The FIG. 7 negative print of the negative selected contour line portions 34' a are therefore obtained, and by reason of the SHIFT, tapered ends of these lines are also effected for the same reasons as described with reference to the FIG. 5 print.

Using the print 36 showing the remaining portions 330 of the contour lines varying in width between maximum and minimum, as above-described, then using the print 37 showing the select portions 34'a of the contour lines varying in width, a final print 38, as shown in FIG. 8, is produced in any conventional manner as, for example, on a piece of white-faced film so that the select contour line portions 34 'a will be printed in the positive and the remaining contour line portions 330 will be printed in the negative. A grey or off-white portion of the final print 38 between each of the contour lines will remain after such printing operation. In such manner, positive and negative contour lines are printed on the final print such that those portions of each contour line depicting a hill or valley facing toward the imaginary ray of light from the northwest quadrant of the print are light lines and the remaining lines are dark, i.e., those lines which represent the side of the hill or valley facing away from the imaginary ray of light shining from the northwest quadrant. The final print 38 is precisely the same as obtained in accordance with the process set forth in my prior aforementioned patent except that it is obtained in a more expeditious manner and without the use of a negative mask or a shifted overlay of the positive transparency, negative mask and negative transparency as disclosed therein.

It should be noted that other objects of the planimetry, i.e., the natural and cultural features of the terrain other than the relief lines, may be produced on the final print 38 or on either the prints 36, 37. For example, the planimetry could be provided on the print 36 before exposure through the FIG. 4 overlay. Many other approaches to achieve this end could also be used. However, the final print 38 shown in FIG. 8 does not show these features of the planimetry only in the interest of clarity.

A process has therefore been disclosed herein for the production of a topographical map having a contour relief effect without the need for any special materials or special skills. Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A photo-mechanical process for producing a relief contour effect for a topographical map, including the steps of:

providing a positive transparency form of the topographical map contour lines;

producing a negative transparency form from said positive transparency form;

masking a select portion of the topographical map contour lines on said negative transparency form to obtain a positive mask;

overlaying said positive transparency fonn and said masked negative transparency form so that their contour lines are coincident;

shifting said overlaid positive transparency form so as to expose the remaining portion of the topographi cal map contour lines;

firstly, printing through said shifted overlay and obtaining a positive print of said remaining portion of the map contour lines,

secondly, individually printing through each said negative transparency form, through said positive mask and through said positive transparency form of said shifted overlay and obtaining a negative print of said select portion of the map contour lines; and

producing a final print from said positive and negative prints in a manner whereby said remaining portion and said select portion contour lines are in the negative and positive, respectively, and are each tapered along their length by reason of said shifting.

2. The process according to claim 1 wherein said positive mask is obtained by shading a portion of each contour line which depicts a hidden side of any number of elevations when viewing'said elevations at a 45 angle.

3. The process according to claim 1 wherein said positive transparency form is shifted along a 45 angle with respect thereto. 

2. The process according to claim 1 wherein said positive mask is obtained by shading a portion of each contour line which depicts a hidden side of any number of elevations when viewing said elevations at a 45* angle.
 3. The process according to claim 1 wherein said positive transparency form is shifted along a 45* angle with respect thereto. 